C++ Array Quiz - MCQ Questions and Answers

Welcome to our blog post "C++ Array Quiz - MCQ Questions and Answers," a tailored challenge for anyone looking to test and enhance their understanding of arrays in C++. Perfect for students, programming enthusiasts, and seasoned developers alike, this quiz covers a range of topics from the basics of array initialization to more complex operations and concepts. 

Each question is designed not only to test your knowledge but also to provide insightful explanations that aid in learning and retention. Whether you're preparing for an exam, a job interview, or just looking to refresh your C++ skills, these carefully curated multiple-choice questions are here to guide your learning journey. So, ready your minds, and let's dive into the world of C++ arrays!

1. How is an array declared in C++?

a) dataType arrayName[size];

b) array dataType[size];

c) dataType[size] arrayName;

d) arrayName[size] dataType;

Answer:

a) dataType arrayName[size];

Explanation:

An array in C++ is declared by specifying the data type of its elements, followed by the array name and its size in square brackets.

2. What is the default value of elements in an uninitialized array in C++?

a) Null

b) 0

c) Garbage values

d) It depends on the compiler

Answer:

c) Garbage values

Explanation:

Uninitialized array elements in C++ contain garbage values (i.e., whatever value is already at the memory location).

3. How do you access the third element in an array named 'data' in C++?

a) data[2]

b) data[3]

c) data(2)

d) data(3)

Answer:

a) data[2]

Explanation:

Array indices in C++ start from 0, so the third element is accessed using data[2].

4. Which of the following array declarations is correct in C++?

a) int numbers[5] = {1, 2, 3, 4, 5};

b) float rates[] = {2.5, 3.0, 4.5, 5.5};

c) char name[10] = "John";

d) All of the above

Answer:

d) All of the above

Explanation:

All these declarations are correct ways to declare arrays in C++.

5. Can the size of an array be changed at runtime in C++?

a) Yes, always

b) No, never

c) Only for dynamic arrays

d) Only if it is a global array

Answer:

b) No, never

Explanation:

In C++, the size of an array is fixed at compile-time and cannot be changed at runtime.

6. What is a multidimensional array in C++?

a) An array with elements of different types

b) An array with functions as elements

c) An array of arrays

d) An array with more than 100 elements

Answer:

c) An array of arrays

Explanation:

A multidimensional array in C++ is an array whose elements are themselves arrays.

7. How do you initialize a two-dimensional array in C++?

a) Using nested loops

b) Using multiple one-dimensional arrays

c) Using a single initializer list with commas

d) Using nested initializer lists

Answer:

d) Using nested initializer lists

Explanation:

A two-dimensional array is initialized using nested initializer lists, each representing a row of the array.

8. What does array decay refer to in C++?

a) Conversion of an array into a single value

b) Loss of array type information and conversion to a pointer

c) Physical degradation of an array over time

d) Decrease in array size at runtime

Answer:

b) Loss of array type information and conversion to a pointer

Explanation:

Array decay is the process where an array loses its type and size information and becomes a pointer to its first element.

9. What is the output of the following C++ code?

   int arr[3] = {0};
   printf("%d %d %d", arr[0], arr[1], arr[2]);

a) 0 0 0

b) Garbage values

c) Error

d) 0 followed by garbage values

Answer:

a) 0 0 0

Explanation:

The array is initialized with all elements set to 0, so the output will be 0 0 0.

10. Which of the following statements about arrays in C++ is correct?

a) Arrays can store elements of different data types

b) Array indices start at 1

c) The size of an array must be a constant expression

d) Elements in an array are accessed using parentheses

Answer:

c) The size of an array must be a constant expression

Explanation:

In C++, the size of an array must be known at compile time and must be a constant expression.

11. What is a pointer to an array in C++?

a) A variable that points to the first element of an array

b) A special type of array

c) A function that returns an array

d) An array of pointers

Answer:

a) A variable that points to the first element of an array

Explanation:

A pointer to an array in C++ is a variable that stores the address of the first element of the array.

12. How do you pass an array to a function in C++?

a) By specifying the array elements individually

b) By passing the array name

c) By passing the first element of the array

d) By creating a copy of the array

Answer:

b) By passing the array name

Explanation:

In C++, an array is passed to a function by passing the array name, which is a pointer to the first element of the array.

13. Can an array contain a pointer in C++?

a) Yes

b) No

c) Only in special cases

d) Only if it is a void pointer

Answer:

a) Yes

Explanation:

An array in C++ can contain pointers as its elements.

14. What is the relationship between arrays and pointers in C++?

a) They are completely unrelated

b) They are the same thing

c) Arrays can be treated as pointers

d) Pointers can only point to single values, not arrays

Answer:

c) Arrays can be treated as pointers

Explanation:

In C++, arrays and pointers are closely related. An array name can be treated as a pointer to the first element of the array.

15. What is the output of the following C++ code?

 int arr[] = {1, 2, 3};
   printf("%d", *(arr + 1));

a) 1

b) 2

c) 3

d) Error

Answer:

b) 2

Explanation:

The expression *(arr + 1) is equivalent to arr[1], which accesses the second element of the array, giving the output 2.

16. How can you dynamically allocate an array in C++?

a) Using the malloc() function

b) Using the new operator

c) By declaring the array with a variable size

d) Using the create() function

Answer:

b) Using the new operator

Explanation:

Dynamic arrays in C++ can be allocated using the new operator, which allocates memory on the heap for the array.

17. What is the correct way to deallocate a dynamically allocated array in C++?

a) delete[]

b) delete

c) free()

d) remove()

Answer:

a) delete[]

Explanation:

To deallocate a dynamically allocated array in C++, the delete[] operator should be used. This ensures that the memory allocated for the array is properly freed.

18. What is the purpose of a range-based for loop in C++?

a) To iterate over each element of an array

b) To execute a loop a specific number of times

c) To create an array with a specific range

d) To compare elements in an array

Answer:

a) To iterate over each element of an array

Explanation:

The range-based for loop in C++ (introduced in C++11) allows for iterating over each element in a container, such as an array, in a simpler and clearer way than traditional for loops.

19. In C++, what is an array of arrays commonly known as?

a) Pointer array

b) Multidimensional array

c) Double array

d) Nested array

Answer:

b) Multidimensional array

Explanation:

An array of arrays in C++ is commonly referred to as a multidimensional array, typically used to represent structures like matrices.

20. How do you initialize an array to zero in C++?

a) int arr[10] = {0};

b) int arr[10] = {};

c) int arr[10]();

d) Both a) and b)

Answer:

d) Both a) and b)

Explanation:

In C++, an array can be initialized to zero by either setting the first element to zero (as in int arr[10] = {0};) or leaving the initializer list empty (as in int arr[10] = {};). Both methods will set all elements to zero.